収蔵 and 展示: keeping objects and putting them on display
Compare 収蔵 for a donated painting or stored materials with 展示 for displayed pottery or a size check at a store. Separate collection, storage, display, and observation without assuming a purchase, public access, or an unstated storage period.
収蔵: taking an object into a collection
収蔵 (しゅうぞう) concerns collecting or storing objects. 「美術館は寄贈された絵画を収蔵した。」 is translated as “The museum added the donated painting to its permanent collection.” The painting was donated, and the museum took it into its collection. The English translation specifies a permanent collection for this example; the Japanese sentence does not independently state a required duration of storage.
「地下の倉庫には貴重な資料が収蔵されている。」 means “Valuable materials are stored in the basement storage room.” Here the focus is the stored state of valuable materials and their location in a basement storage room. This example does not state that the storage is permanent or that the materials can never be displayed.
展示: showing an object to be viewed
展示 (てんじ) focuses on putting something on display. 「博物館では古代の土器を展示している。」 means “The museum displays ancient pottery.” The museum displays ancient pottery. The sentence tells us about the display, without explaining how the museum obtained the pottery.
「店頭の展示を見て、新しい掃除機の大きさを確かめた。」 means “I checked the new vacuum's size from the store display.” The observer used the store display to check the size of a new vacuum. The check took place, but the sentence does not say that the observer purchased the vacuum or completed a payment.
Read the action stated for each object
Keeping an object and showing it are different focuses. An object in a collection may also be displayed, so these examples do not support a rule that everything collected is private or that displayed objects cannot be collected. Taking in the donated painting does not itself establish that it was put on public display.
Keep the wording of each example within its scope: the English phrase 'permanent collection' belongs to the donated-painting translation, while the basement example describes stored materials. For 展示, distinguish the institution's display from the observer's later size check. Neither keeping nor viewing an object by itself tells us that someone bought it.
Does 「美術館は寄贈された絵画を収蔵した。」 establish that the museum bought the painting or displayed it to the public?
Show the answer and why
No. It says that the museum took a donated painting into its collection. Buying it and displaying it to the public are not stated. The English translation's 'permanent collection' describes this example; it does not add permanence to the separate basement-storage example.